help append dialog: append
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Title
[D] append -- Append datasets
Syntax
append using filename [filename ...] [, options]
You may enclose filename in double quotes and must do so if filename
contains blanks or other special characters.
options description
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generate(newvar) newvar marks source of resulting observations
keep(varlist) keep specified variables from appending dataset(s)
nolabel do not copy value-label definitions from dataset(s) on
disk
nonotes do not copy notes from dataset(s) on disk
force append string to numeric or numeric to string without
error
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Menu
Data > Combine datasets > Append datasets
Description
append appends Stata-format datasets stored on disk to the end of the
dataset in memory. If any filename is specified without an extension,
.dta is assumed.
Stata can also join observations from two datasets into one; see [D]
merge. See [U] 22 Combining datasets for a comparison of append, merge,
and joinby.
Options
generate(newvar) specifies the name of a variable to be created that will
mark the source of observations. Observations from the master
dataset (the data in memory before the append command) will contain 0
for this variable. Observations from the first using dataset will
contain 1 for this variable; observations from the second using
dataset will contain 2 for this variable; and so on.
keep(varlist) specifies the variables to be kept from the using dataset.
If keep() is not specified, all variables are kept.
The varlist in keep(varlist) differs from standard Stata varlists in
two ways: variable names in varlist may not be abbreviated, except by
the use of wildcard characters, and you may not refer to a range of
variables, such as price-weight.
nolabel prevents Stata from copying the value-label definitions from the
disk dataset into the dataset in memory. Even if you do not specify
this option, label definitions from the disk dataset never replace
definitions already in memory.
nonotes prevents notes in the using dataset from being incorporated into
the result. The default is to incorporate notes from the using
dataset that do not already appear in the master data.
force allows string variables to be appended to numeric variables and
vice versa, resulting in missing values from the using dataset. If
omitted, append issues an error; if specified, append issues a
warning.
Examples
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Setup
. webuse even
. list
. webuse odd
. list
Append even data to the end of the odd data
. append using http://www.stata-press.com/data/r11/even
List the results
. list
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Setup
. sysuse auto
. keep if foreign == 0
. save domestic
. sysuse auto, clear
. keep if foreign == 1
. keep make price mpg rep78 foreign
Append domestic car data to the end of the foreign car data and only keep
variables make, price, mpg, rep78, and foreign from domestic car data
. append using domestic, keep(make price mpg rep78 foreign)
List the results
. list
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Setup
. sysuse citytemp, clear
. keep if region == 4
. save west
. sysuse citytemp, clear
. keep if region == 3
. save south
. sysuse citytemp, clear
. keep if region == 1
Append temperature data for the West region (region==4) and the South
region (region==3) to the end of the data for the New England region
(region==1), and generate new variable filenum to indicate from which
file each observation came. Do not load value-label definitions from
west.dta or south.dta.
. append using west south, generate(filenum) nolabel
List the results
. list
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Also see
Manual: [D] append
Help: [D] cross, [D] joinby, [D] merge, [D] save, [D] use
